发表机构
Jinan Institute of Quantum Technology and Jinan branch, Hefei National Laboratory; State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, and Frontier Science Center for Quantum Information; Data Communication Science and Technology Research Institute; International Quantum Academy（济南量子技术研究院与合肥国家实验室济南分部; 清华大学物理系低维量子物理国家重点实验室及前沿科学中心量子信息; 数据通信科学技术研究所; 国际量子学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对可变长度边信道安全量子密钥分发的相干攻击，应用熵不确定性关系和量子剩余哈希引理框架，提出安全证明方法，降低脉冲要求，确定安全密钥长度条件，阐明集中界适用性，提升了SCS协议实用价值及密钥率公式安全依据。
AI 中文摘要
通过应用熵不确定性关系（EUR）框架和量子剩余哈希引理（QLHL），我们引入了一种针对相干攻击的可变长度边信道安全（SCS）量子密钥分发（QKD）的安全证明方法。该方法将可组合安全性重新构建为相位误差的统计波动问题，通过可观测量和虚拟可观测量直接证明针对相干攻击的安全性。它为SCS协议产生了紧密的密钥率，与采用后选择技术的先前工作相比，脉冲要求降低了两个多数量级。我们证明，利用未标记比特无比特翻转错误这一事实，通过纠错后的实际信息泄漏和每个状态的纠错后统计来计算最终密钥率，可在纠错后确定SCS协议的安全密钥长度。我们进一步确定了在更广泛的QKD协议类中，纠错后可确定最终密钥长度的充分条件。在EUR和QLHL框架下，我们阐明了几种常用集中界对可变长度QKD的适用性及其实施的适当方式。这项工作提高了SCS协议的实用价值，并阐明了实际可变长度QKD实现中使用的密钥率公式的安全依据。
英文摘要
By applying the framework of entropic uncertainty relation (EUR) and the Quantum Leftover Hash Lemma (QLHL), we introduce a security-proof method for variable-length side-channel-secure (SCS) quantum key distribution (QKD) against coherent attacks. This method reframes composable security as a statistical fluctuation problem of phase errors, enabling direct proofs against coherent attacks through observables and virtual observables. It yields tight key rates for the SCS protocol and reduces pulse requirements by over two orders of magnitude compared to prior works that employ the post-selection technique. {Utilizing the characteristic of the SCS protocol that it has no untagged-bit bit-flip errors, we prove that the secure key length for the SCS protocol can be determined after Cascade error correction, using its actual parity disclosures. We also explain how the same argument extends to protocols with compatible bit-error-pattern and phase-error measurements.} We further identify sufficient conditions under which the final key length may be determined after error correction in a broader class of QKD protocols. Under the framework of EUR and QLHL, we clarify the applicability of several commonly used concentration bounds to variable-length QKD and the appropriate manner of their implementation. This work enhances the practical value of the SCS protocol and clarifies the security justification of key-rate formulas used in practical variable-length QKD implementations.
